I get what you are saying and have seen it. Since then I print everything using the PDF995 printer driver which can be downloaded from this website. Then print the PDF file and the picture comes out clear.

Download and install the PDF995, then when you go to print something look in the printer properties box and change your printer to the PDF995. This is freeware, so it will have an ad with it, but will create the map in a PDF format which can be printed resulting in a clearer picture.